Prepare the Cherry Glaze: Pit the cherries and combine them with dark brown sugar, honey, orange juice, lemon juice, cinnamon stick, and allspice in a saucepan. Simmer for about 10 minutes, then strain the glaze.

Simmer the Gammon: In a large pot, cover the gammon with water and add chopped carrots, celery, and onion. Boil, then simmer for 2 hours until tender. Remove and discard the vegetables.

Cool and Preheat Oven: Let the gammon cool for 15-20 minutes and preheat the oven to 190°C (374°F).

Roast the Fruit: Line a roasting tray with parchment, arrange the oranges and pineapple, drizzle with olive oil and sprinkle with salt. Roast for 15-20 minutes.

Prepare Gammon for Baking: Remove the skin from the gammon, score the fat in a diamond pattern, and brush with the reserved cherry glaze.

Bake the Ham: Place the gammon in the oven and bake at 190°C (374°F) for 20-30 minutes, basting every 10 minutes. Increase the oven to 220°C (428°F) for the last 5 minutes.

Serve: Let the ham cool for 10 minutes, slice, and serve with roasted fruits.